Gravel cycling or biking is largely considered to be a mix between road and mountain biking. Even though this cycling style has “gravel” in its name, gravel biking includes riding on a variety of surfaces, including beaches, bridleways and stretches of road in between. As Steven Rindner says that basically gravel biking means to ride on any unpaved surface, even if it is a completely flat, well-travelled dirt road.

Steven Rindner offers a general overview of gravel biking 

Roots of gravel biking can be tracked way back to the early 2000s, as cyclists started to explore unpaved trails and roads on traditional road bikes. It largely evolved out of the mountain bike boom that was witnessed in the 80s, as cyclists in Northern California adapted their bikes and started to explore rougher terrain. With time, an increasing number of cyclists across the world sought greater freedom, especially in regards to tackling a wide range of terrains. With this, bike manufacturers recognized the need of more specialized vehicles, and that is how gravel bikes emerged as a category of their own. These bikes combine the speed and agility of typical road bikes with the durability and ruggedness needed for off-road adventures.

Gravel bikes typically sit somewhere between road bikes and mountain bikes. They combine the features of both while offering a range of unique advantages.

• Gravel bikes typically have wider tires than road bikes. These tires typically range from 35-50mm, and also have a greater tire clearance in comparison to that of road bikes. 
• Gravel bikes have drop-handlebars while mountain bikes have flat-bars. 
• Gravel bikes have quite relaxed geometry. They allow cyclists to navigate rough terrain comfortably, absorb vibrations effectively, as well as easily maintain control on loose surfaces.
• Gravel bikes generally come equipped with disc brakes that ensure reliable stopping power in varying conditions. They may also have their own dedicated group-sets so that cyclists can shift gear more easily in steep climbs on unpaved roads.

Mountain bikes tend to excel in extreme off-road environments, but they would be an overkill for gravel paths that are less demanding. Gravel bikes strike a good balance by providing speed and efficiency on smooth surfaces, agility on trails, as well as the versatility to handle diverse types of riding styles. Due to their flexibility, gravel biking has become pretty popular among cyclists who seek a cycling experience that combines speed and diversity. As Steven Rindner mentions, gravel bikes are today widely favoured by many urban cyclists who desire improved dexterity and speed on city roads and pathways. These bikes are somewhat costlier and elegant counterparts of flat-bar hybrid bikes.

Gravel bikes would open up a world of adventures for cyclists who want to explore beyond paved roads. Designed for versatility, they have the capacity to navigate gravel paths, fire roads, and scenic backcountry trails that traditional road bikes struggle with. These bikes are built to handle diverse terrains. They perform well on smooth asphalt, rugged gravel, and even light single-track trails. The adaptability of gravel bikes makes them an all-in-one solution, reducing the need for multiple specialized bikes.